Alloy



Patented Sept. 11, 1928.

UNITED STATES PATENT OFFICE.

SEWELL E. WINSLOW, OF BRIDGEPORT, CONNECTICUT, ASSIGNOB, BY MESNE ASSIGN- MEN'IS, 'IO CONSOLIDATED ASHCROFT HANCOCK COMPANY, OF NEW YORK, N. Y., A

GORPORA'IION OF DELAWARE.

ALLOY.

Ho Drawing.

The present invention relates to the preparation of an alloy comprising the elements of Monelmet'al and substantial additions of tin.

In its general aspect, this invention comprises the formation of an alloy byadding predetermined quantities of tin to an alloy derived from a naturally occurring ore reduction or synthetic alloy consisting essentially of nickel and copper (in which the proportions of these elements may vary but are in general characterized by a predominance of the nickel over copper) or by (30111- hining all threemetals in appr priate proportions, and pr ducing herefrom a homogeneous composition or alloy, as bymelting. For this purpose, Monel metal, which is an alloy resulting from the reduction of the natural ores of copper and nickel or which can be made by the synthetic aggregation of the metals themselves into an alloy of equivalent composition, is especially desirable. A

typical composition of this alloy is characterized by the proportions of 67% nickel, 28% copper and 5% of other metals, as impurities, such as silicon, manganese, iron, and carbon. But these ratios may, and ordinarily will vary in practice within comparatively wide limits according to the source of the ores used. the processes and practices employedin reducing the ores and in making theinitial or final alloy, and upon the nature of the casting operation itself.

A typical mode of preparation will be described as representative of any equivalent or suitable procedure for the production of the alloy, and as applied to a typical combina-- tion and proportion of Monel metal with tin.

The Monel metal may be prepared by reducing a mixture of the natural ores of these metals in the usual manner. Manganese or other deoxidizer may be added to the melt, and other reduced metals may be present as impurities. The resulting alloy may be employed in melted condition or in the form of ingots. A typical Monel metal thus produced contained approximately 67% nickel, 28% copper and 5% impurities, the latter including 1.25% Si, 2.32% Fe., 0.49% NIH and 0.24% carbon.-

Usually, the nickel-copper alloy will be employed in the form of shot. In this case, a weighed charge of the Monel metal shot is first melted, preferably in a graphite crucible,

Application filed March 4, 1924. Serial No. 696,825.

the top surface of the molten metal being protected from the air by a. layer of char coal. The temperature which has been found'most suitable is that of white heat,- 2700 F. or over. While at this temperature and uniformly fluid, a quantity of tin is added to the batch, which may vary accordmg to the properties desired in the final product, but which should be somewhat in excess of the calculated proportion and preferably 12% or less, by weight, in the final melt. [A part of the tin acts as a deoxidizer of the melt and Forms a slag which rises to the surface] Slag is removed and the lear molten metal is then poured into a bright cherry red"4hot graphite crucible. Manganese deoxidizer is then added and stirred in, the slag removed, and the top of the charge covered with charcoal.

The charge is then ready to our into the molds for casting into the final f drins desired, and this is preferably done while the metal 1s still at 'a high temperature. The structure of castings so produced is characterized by what may be termed a small columnar structure, as distinguished from ,a coarse structure on the one hand and a fine grained structure on the other.

The resulting alloy is found to possess remarkable properties distinct both from those of the original constituents and from those of Monel metal, but retaining all of the desirable characteristics of the latter, the newly acquired properties being substantially addi tive. Especially noteworthy are the greatly improved casting qualities of the new alloy or composition, its freedom 'from blow holes and uneven structure, and its increased hardness. But, in addition to these improvements, the tensilestrcngth of the resultin product is found to be profoundly affected y the treatment described, and to be greatly increased, even when very small additions of tin are made. lVith proportions of tin amounting to only'l% or less by weight, the tensile strength is found to be inordinately increased. With additional increments of tin the increase in tensile strength of the resulting alloy rapidly continues. When about 12% of tin is present, the hardness is increased so much that the machining of the metal is extremely difficult. In such cases, resort may be had to various grinding and finishing operations with abrasives.

The retention of tensile strength by the new alloy at elevated temperatures is an especially important feature and becomes greater as the proportionate addition of tin is increased up to 12%. Therefore, for purposes involving use at relatively higher temperatures, the alloy will be made with a relatively larger percentage addition of tin, governed by the temperature to be provided for, and the resultmg product will possess a greater initial tensile strength and will retain this tensile strength to ,a higher temperature, according ly. It is found also that the elastic limit of the new alloy is initially higher, and is higher at any given temperature, the greater the relative addition of tin.

It is to be noted that the proportions of nickel and copper which are present in Monel metal bear an atomic ratio to each other of from 3 to 1 to 5 to 2. What significance this specific ratio may have with respect to the properties of Monel metal or to the alloy which is obtained in accordance with the invention as above described, is not known. But it is found generally desirable that this ratio be substantially preserved. This is effected by adding the required proportion of tin without otherwise altering the relative amounts of the metals employed.

I claim:

1. An alloy or composition of metals, composed substantially of nickel, copper and tin, the nickel and copper in approximately the atomic proportions of ten to four and tin in an atomic proportion not greater than one.

2. An alloy or composition of metals, composed substantially of nickel, copper and tin, the nickel and copper in approximately the atomic proportions in which they are ordinarily present in Monel metal and not more than one atomic equivalent of tin.

'3. An alloy or composition of metals, composed substantially of nickel, copper and tin, in approximately the atomic proportions of ten. four and one, respectively, and characterized by a high degree of hardness, though susceptible to machining and the like.

4. An alloy or metallic composition, comprising nickel, copper and tin in approximately the proportions of 60%, 25% and 12%, respectively.

5. An alloy or composition of metals essentially composed of nickel, copper and tin, in proportions of approximately two to three tignes as much nickel as copper and 1% to 12% 0 tin.

6. An alley or composition of metals essentially composed of nickel, copper and tin, in proportions of approximately two to three times as much nickel as copper and approximately three times as much copper as tin.

7. An alloy or composition'of metals composed essentially of nickel, copper and tin in proportions of two to three times as much nickel as copper and two to three times as much copper as tin.

Signed by me at Bridgeport, Connecticut. this 18 day of February, 1924.

SEWELL E. WINSLOW. 

